1. Field
Aspects of the present invention relate to a touch screen panel and a manufacturing method thereof.
2. Description of the Related Art
A touch screen panel is an input device that allows a user's instruction to be inputted by a user's hand or object selecting an instruction content displayed on a screen such as an image display device. To this end, the touch screen panel is formed on a front face of the image display device to convert a contact position into an electrical signal. Here, the user's hand or object is directly in contact with the touch screen panel at the contact position. Accordingly, the instruction content selected at the contact position is inputted as an input signal to the image display device.
Since such a touch screen panel can be used instead of a separate input device connected to an image display device, such as a keyboard or mouse, use of the touch screen panel has increased. Touch screen panels are divided into a resistive overlay touch screen panel, a photosensitive touch screen panel, a capacitive touch screen panel, and the like. Among these touch screen panels, the capacitive touch screen panel converts a contact position into an electrical signal by sensing a change in capacitance formed between a conductive sensing cell and an adjacent sensing cell, ground electrode or the like, when a user's hand or object is in contact with the touch screen panel.
In the capacitive touch screen panel, the structure of electrodes is differently formed depending on a reading mode of a touch at a touch point on a touch screen panel. A mode used in touch screen panels is the mode in which a coordinate is calculated by separately forming electrodes on the X-axis and electrodes on the Y-axis. However, in the mode, hereinafter referred to as a 2 layer TSP, touch electrodes are necessarily formed into a two-layer structure. Hence, the 2 layer TSP has expensive unit cost and problems such as electrostatic discharge (ESD).
On the other hand, a method, hereinafter referred to as a 1 layer TSP, in which touch electrodes are formed into a one-layer structure, has inexpensive unit cost and a structure resilient to ESD. Therefore, the development of the 1 layer TSP has recently been advanced. The 1-layer TSP has difficulty in recognizing an X and Y coordinate when a multi-touch is inputted by a user. However, as the recognition for the multi-touch has recently been achieved with the development of algorithm technologies, it is expected that multi-touch applications will be increased.
A film-type 1 layer TSP can be easily manufactured into a simple structure having a two-layer silver interconnection separated into an indium tin oxide (ITO) electrode and an insulating layer is formed to calculate a touch position on the X-axis and Y-axis in a single layer. However, when a glass-type 1 layer TSP is manufactured by applying the manufacturing process of a thin film transistor, the manufacturing process necessarily goes through five mask processes, like the 2 layer TSP. This is because, in the glass-type 1 layer TSP, processes of forming metals are individually performed with an insulating layer interposed therebetween so as to form the two-layer interconnection separated in the film-type 1 layer TSP.
That is, the manufacturing process of a related art 1 layer TSP includes: forming a first electrode layer, having an even-numbered row metal electrode portion or odd-numbered row metal electrode portion, on a substrate using a first mask and covering the first electrode layer with an insulating layer; exposing a top of the first electrode layer using a second mask; forming a second electrode layer, having an odd-numbered row metal electrode portion or even-numbered row metal electrode portion, using a third mask; forming transparent electrodes (ITO) used as sensing cells, which are also referred to as touch electrodes, using a fourth mask and covering the transparent electrodes (ITO) with an insulating layer; and exposing position detecting lines formed at the outline of a touch active area in the touch screen panel using a fifth mask. Accordingly, the related art touch screen panel is manufactured using five masks.
However, the manufacture of masks increases development costs. Particularly, the number of masks is related to a manufacturing burden and complexity upon the manufacturing and processing department, and is linked directly to manufacturing cost. Accordingly, when touch screen panels are manufactured using the related art described above, a large number of masks are necessarily used. Therefore, manufacturing cost is increased, and processing efficiency is degraded.